| 摘要 |
PURPOSE:To stabilize a light quantity, and to obtain an exact signal by supporting elastically one surface of a fitting plate to which a phase plate and a photodetector are fitted, and also rotating the other surface and making it contact to the end part of an encoder shaft. CONSTITUTION:A code wheel 3 is fixed to an encoder shaft having a center recessed part 6 on the end part, and an opposed phase plate 2 and a photodetector 4 are fixed to a fitting plate 7. A center recessed part 8 opposed to the encoder shaft 5 is provided in the center of this fitting plate 7. A groove 9 provided on the circumferential edge part so as to slide in the thrust direction of the encoder shaft 5 is fitted to a rib 11 in the direction of the encoder shaft 5 provided on the inside surface of a casing 10. Also, the back of this fitting plate 7 is supported elastically to the cord wheel side in the thrust direction by a spring 12, and on the other hand, this fitting plate 7 and the encoder shaft 5 contact to each other through a ball 13 interposed between the recessed parts 6, 8. |
